The impact of the silica as the spacer layer on the absorption of the structure composed of WSe2 in the presence of plasmonic effect

 Two-dimensional materials such as transition metal dichalcogenides TMDCs with direct band gaps have opened a new horizon for application in photonics and optoelectronic elements. Of various TMDCs, the WSe2 monolayer is chosen to study its absorption in the presence of the gold as a plasmonic layer and SiO2 as the spacer layer with alternative layer’s positions. Optical properties of these structures are calculated based on the transfer matrix method, TMM, in the visible wavelength region. We found that the presence of the spacer layer between the WSe2 and gold layer enhances the absorption significantly. In an optimal design and in the wavelength of 324 nm, while thickness of the spacer layer is 38 nm, the absorption is reached to 97. Our findings can be applied for designing any desirable optical absorbers for high performance photovoltaic devices.